HEAT DETECTOR WITH FREQUENCY FILTRATION Russian patent published in 1998 - IPC

FIELD: electric fire alarm devices for early fire detection. SUBSTANCE: differential thermocouple converts pulses of convection flow over fire into electric signal. Time constants of thermocouple junctions provide detection of frequency range which is characteristic for fire. Signals from all thermocouples are added, amplified and converted by means of amplitude discriminator into pulse signal of constant amplitude which is accumulated in integrator. When signal reaches some threshold, threshold gate fires and actuator is turned on. EFFECT: increased reliability, increased validity of early fire detection. 1 dwg